Camshaft adjusters are used in internal combustion engines for varying the timing of the combustion chamber valves. The adaptation of the timing to the present load and rotational speed reduces fuel consumption and emissions. A widely used design is the vane-type adjuster. Vane-type adjusters have a stator, a rotor and a drive input wheel. The rotor is usually connected in a rotationally conjoint manner to the camshaft. The stator and the drive input wheel are likewise connected to one another, wherein the rotor is coaxial with respect to the stator and is situated within the stator. The rotor and stator form oil chambers (vane cells) which can be charged with oil pressure and permit a relative movement between the stator and rotor. Furthermore, the vane-type adjusters have a variety of sealing covers. The assembly of stator, drive input wheel and sealing cover is formed by multiple screw connections.
A camshaft adjuster is known from U.S. Pat. No. 6,666,181 B2. The rotor 30, the drive output element, has a bypass in addition to the known hydraulic medium ducts. The bypass conveys the displaced hydraulic medium from a working chamber into the oppositely acting working chamber. When the bypass is covered by the stator, the drive input element, hydraulic medium flow is stopped. The rotor is now situated in the central position. The bypass is controlled by a control piston which can enable or block the hydraulic medium flow from a bypass to a hydraulic medium duct. The conventional hydraulic medium ducts are equipped, in a known way, with check valves in order to utilize the alternating camshaft torques for adjustment, in that, at the time of an alternating camshaft torque, the hydraulic medium volume to be displaced is diverted from one working chamber into the oppositely acting working chamber. In the corresponding axial position of the control piston, those hydraulic medium ducts which permit said transfer in the desired adjustment direction of the rotor are connected into the hydraulic medium flow.